The present invention relates to a buckle device, into which a tongue is inserted and engaged when seat belt is put on by an occupant of a vehicle and a method for connecting said buckle device in a seat belt unit, which is provided on a seat of an automobile or other vehicle for restraining and protecting the occupant in an emergency such as vehicle collision. In particular, the invention relates to a buckle device having a buckle cover where an upper cover and a lower cover are connected together, and to a method for connecting said buckle device.
At present, seat belt unit is provided on seat of various types of vehicle such as automobile in order to protect the occupant of the vehicle in an emergency such as vehicle collision. The seat belt unit of this type generally comprises a tongue attached to the seat belt and a buckle device, with which the tongue is engaged. By engaging or disengaging the tongue and the buckle device, the seat belt can be easily put on or off.
In a conventional type buckle device, a buckle cover is used to cover the mechanism of the buckle. This buckle cover is generally divided into upper and lower parts, i.e. the buckle cover is formed by connecting the upper cover and the lower cover together. As the conventional methods to connect these two covers, there are welding method, fastener method and screw method.
The welding method is a method to connect the upper and the lower covers by welding. By the fastener method, a female type engaged portion is formed on the upper cover, and a male type engaging portion is provided on the lower cover. After inserting and engaging the engaging portion into the engaged portion, a lock pin is used to firmly hold the engagement between the engaging portion and the engaged portion. Further, in the screw method, the upper cover and the lower cover are overlapped on each other, and they are connected by screw.
However, it is not possible to confirm whether these covers are completely welded or not in the welding method, and problem arises that the reliability of connection is not sufficient. In the fastener method, the lock pin must be struck from outside. Thus, the lock pin thus struck or the striking point is exposed to outside. This not only impairs external appearance but also a special tool for striking the lock pin is required. Further, in the screw method, direct exposure of the screw to outside impairs external appearance. Also, outsiders may mischievously remove the screw and expose internal buckle mechanism to outside.